Compute & Storage Questions
Part of the Cloud Computing Roadmap
In short
"Block or object storage?" and "container or serverless?" are favourites because memorised definitions fall apart with one follow-up. Interviewers want to hear when you'd pick each and why.
'When would you choose a container over serverless?' or 'explain the difference between block and object storage' — testing genuine understanding from Phases 4-5, not memorized definitions.
Think of it like this
The lab viva
In a practical viva, the examiner doesn't ask you to recite the definition of titration. She asks why you used this indicator and what would happen if you added acid faster. Knowing the reason behind each step is what gets marks.
Watch it happen
Block vs object storage
Block (EBS, disks)
- Attached to one server like a disk
- Low latency, good for databases
- You pay for provisioned size
Object (S3, Blob)
- Accessed over HTTP by key
- Huge scale, many readers at once
- Pay for what you store
Databases and OS disks on block storage; uploads, backups, logs and static files on object storage.
The big ideas
What you need to know
File storage too
Shared file systems like EFS or Azure Files let many servers mount the same folder. Know the third option.
Containers fit long-running
Steady traffic, custom runtimes, long tasks or many services sharing a cluster suit containers.
Serverless fits spiky
Event-driven, bursty or low-traffic work suits functions. Watch time limits and cold starts.
VMs still matter
Legacy apps, special licences or full OS control often mean plain VMs. Saying so shows maturity.
How it works
Answering "container or serverless?"
- 1
Ask about traffic
Steady all day, or quiet with sudden bursts? Bursts lean serverless.
- 2
Ask about run time
Jobs longer than a function's time limit, or always-on connections, lean containers.
- 3
Ask about the team
Do they already run Kubernetes? Reusing skills is a valid reason.
- 4
Pick and give a trade-off
"Serverless here for cost at low traffic, but I'd watch cold starts on the checkout path."
Save yourself the pain
Common mistakes
Oops
Saying object storage is "just slower block storage".
Do this instead
They're different models: block is a disk for one machine, object is a key-value store over HTTP at huge scale.
Oops
Answering "serverless is always cheaper".
Do this instead
It's cheap at low or spiky traffic. At high steady traffic, containers or VMs can cost less.
Your mission
Ten-question drill
Quick check
Five web servers need to read and write the same uploaded files as a shared folder. Which fits best?
Go deeper
- 1Review Phases 4-5 and practice explaining each service choice in plain language.
- 2Prepare to justify a compute or storage choice for a specific hypothetical workload.
- 3Practice comparing options across multiple providers if your target role expects multi-cloud fluency.
More services & technical at this stop
Networking & Security Questions
Database Questions
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